Bloom

[meetdilip]

Hi, I was suggested to use " Bloom " for the glow effect in one of the threads here. Sadly when I tried Bloom today on a few images with small red and green lines on it ( the rest is black ), there is no glow effect. I am not sure what went wrong. Can we use any layer and apply Bloom to it ? Or, is there any specific condition that needs to be met ? Thanks.

[rich2005]

All depends on the image, however there is the blending option, just the same as layer modes. The mouse wheel will scroll though to try out.

Then the strength slider goes way beyond the extent of the dialogue. Try entering a value manually.

example: https://i.imgur.com/Zry2HmL.mp4

[meetdilip]

I think I got what is going wrong. I am using a single layer for red. That is, the only element in that layer is a red line/box. In that case, bloom does nothing. But when I merge it with the black background, " Bloom " works.

Thanks.

[rich2005]

I sort of guessed that applying bloom on a transparent layer might be the problem. It might be a bug. It is just a blur and with sample merged active the layers under should count.

As an alternative, the gmic plugin has a good glow blur but with a similar restriction, need a solid layer.

[meetdilip]

Thanks. I will check.

What is a solid layer ? 100 % opaque ? Can we use this GMIC plugin if there is a red box and rest of the layer is transparent. I will try using Blur too.

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I think I learned enough to do it with Gaussian Blur.

[rich2005]

This using Ofnuts neon-path-0.2.py  ( apparently superceded by ofn-gradient-along-path.py )

Makes a nice glow effect.